Technetium is a radioactive product of the nuclear fission process. During reprocessing of spent or partially spent fuel from nuclear reactors, the technetium can be released and contaminate other, otherwise good, metals. A specific example is equipment in gaseous diffusion uranium enrichment cascades which have been used to process fuel which was returned from reactors, so-called reactor returns. These returns contained volatile technetium compounds which contaminated the metals in the equipment. Present regulations require that technetium be removed before the metal can be re-used at non-radioactive sites.
Removal of sulfur from steel by the addition of small quantities of manganese is well known. Sulfur tends to concentrate at the grain boundaries, and is an embrittling agent. Thus, the removal of sulfur during the steelmaking process is important to the usefulness of steel. The sulfur removal process uses an alloying element to remove an undesirable element. Sulfur is removed to extremely low levels, while a small excess of the alloying element remains in the steel without damage to its properties.
In addition to the market value of the decontaminated and reprocessed metals, savings can be realized by not having to bury contaminated metals in land fills or store them by some other means. For example, the cost of burying household garbage currently is approximately $85 per ton. Even if the nearby landfills would accept radioactively contaminated metals, the cost would be unacceptable.
Removing the technetium from contaminated metals has two desirable results: First, the large amount of nonradioactive metal produced by the process herein described can be recycled at a much lower cost than virgin metal can be produced. Second, large amounts of radioactively contaminated metal can be reduced to relatively small amounts of radioactive slag and large amounts of essentially uncontaminated metal.